Characterization of biomass comminution for entrained-flow gasification

Abstract

Biomass entrained-flow gasification is one of the most promising conversion technologies for biomass utilization, characterized by high conversion efficiency and environmental friendliness. As a booming technology, the selection of particle size in biomass entrained-flow gasification has been a key issue of concern but has not yet been resolved. In this paper, a hammer mill was used to comminute biomass into powders of various particle sizes; Typical biomass materials including rice husk, rice straw, wood chip, and chinar leaf were selected as experimental materials to analyze the comminuting characteristics of different biomasses. Different screen sizes (SS) ranging from 0.2 mm to 2 mm were utilized to investigate the influence of comminuting particle size. The influence of SS on the characteristics of biomass particles (particle size, particle shape) was analyzed. The characteristic particle size, represented by d90, was extracted and found to exhibit a good linear relationship with the SS. It was confirmed that reducing the particle size effectively reduces the particle anisotropy. Furthermore, the bulking and flow characteristics of different particles was investigated. Despite the increase in bulk and tap densities with decreasing particle size, it is interesting to note that the flowability of the powder first improves and then weakens. Finally, the impact of SS on the comminution energy consumption was investigated and the Bond comminution constants were fitted for the four biomass tested.